// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SOCKET_SOCKS_CLIENT_SOCKET_POOL_H_
#define NET_SOCKET_SOCKS_CLIENT_SOCKET_POOL_H_

#include <memory>
#include <string>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "net/base/host_port_pair.h"
#include "net/dns/host_resolver.h"
#include "net/socket/client_socket_pool.h"
#include "net/socket/client_socket_pool_base.h"

namespace net {

class ConnectJobFactory;
class SocketPerformanceWatcherFactory;
class TransportClientSocketPool;
class TransportSocketParams;

class NET_EXPORT_PRIVATE SOCKSSocketParams
    : public base::RefCounted<SOCKSSocketParams> {
public:
    SOCKSSocketParams(const scoped_refptr<TransportSocketParams>& proxy_server,
        bool socks_v5, const HostPortPair& host_port_pair);

    const scoped_refptr<TransportSocketParams>& transport_params() const
    {
        return transport_params_;
    }
    const HostResolver::RequestInfo& destination() const { return destination_; }
    bool is_socks_v5() const { return socks_v5_; }

private:
    friend class base::RefCounted<SOCKSSocketParams>;
    ~SOCKSSocketParams();

    // The transport (likely TCP) connection must point toward the proxy server.
    const scoped_refptr<TransportSocketParams> transport_params_;
    // This is the HTTP destination.
    HostResolver::RequestInfo destination_;
    const bool socks_v5_;

    DISALLOW_COPY_AND_ASSIGN(SOCKSSocketParams);
};

// SOCKSConnectJob handles the handshake to a socks server after setting up
// an underlying transport socket.
class SOCKSConnectJob : public ConnectJob {
public:
    SOCKSConnectJob(const std::string& group_name,
        RequestPriority priority,
        ClientSocketPool::RespectLimits respect_limits,
        const scoped_refptr<SOCKSSocketParams>& params,
        const base::TimeDelta& timeout_duration,
        TransportClientSocketPool* transport_pool,
        HostResolver* host_resolver,
        Delegate* delegate,
        NetLog* net_log);
    ~SOCKSConnectJob() override;

    // ConnectJob methods.
    LoadState GetLoadState() const override;

private:
    enum State {
        STATE_TRANSPORT_CONNECT,
        STATE_TRANSPORT_CONNECT_COMPLETE,
        STATE_SOCKS_CONNECT,
        STATE_SOCKS_CONNECT_COMPLETE,
        STATE_NONE,
    };

    void OnIOComplete(int result);

    // Runs the state transition loop.
    int DoLoop(int result);

    int DoTransportConnect();
    int DoTransportConnectComplete(int result);
    int DoSOCKSConnect();
    int DoSOCKSConnectComplete(int result);

    // Begins the transport connection and the SOCKS handshake.  Returns OK on
    // success and ERR_IO_PENDING if it cannot immediately service the request.
    // Otherwise, it returns a net error code.
    int ConnectInternal() override;

    scoped_refptr<SOCKSSocketParams> socks_params_;
    TransportClientSocketPool* const transport_pool_;
    HostResolver* const resolver_;

    State next_state_;
    CompletionCallback callback_;
    std::unique_ptr<ClientSocketHandle> transport_socket_handle_;
    std::unique_ptr<StreamSocket> socket_;

    DISALLOW_COPY_AND_ASSIGN(SOCKSConnectJob);
};

class NET_EXPORT_PRIVATE SOCKSClientSocketPool
    : public ClientSocketPool,
      public HigherLayeredPool {
public:
    typedef SOCKSSocketParams SocketParams;

    SOCKSClientSocketPool(int max_sockets,
        int max_sockets_per_group,
        HostResolver* host_resolver,
        TransportClientSocketPool* transport_pool,
        SocketPerformanceWatcherFactory*,
        NetLog* net_log);

    ~SOCKSClientSocketPool() override;

    // ClientSocketPool implementation.
    int RequestSocket(const std::string& group_name,
        const void* connect_params,
        RequestPriority priority,
        RespectLimits respect_limits,
        ClientSocketHandle* handle,
        const CompletionCallback& callback,
        const BoundNetLog& net_log) override;

    void RequestSockets(const std::string& group_name,
        const void* params,
        int num_sockets,
        const BoundNetLog& net_log) override;

    void CancelRequest(const std::string& group_name,
        ClientSocketHandle* handle) override;

    void ReleaseSocket(const std::string& group_name,
        std::unique_ptr<StreamSocket> socket,
        int id) override;

    void FlushWithError(int error) override;

    void CloseIdleSockets() override;

    int IdleSocketCount() const override;

    int IdleSocketCountInGroup(const std::string& group_name) const override;

    LoadState GetLoadState(const std::string& group_name,
        const ClientSocketHandle* handle) const override;

    std::unique_ptr<base::DictionaryValue> GetInfoAsValue(
        const std::string& name,
        const std::string& type,
        bool include_nested_pools) const override;

    base::TimeDelta ConnectionTimeout() const override;

    // LowerLayeredPool implementation.
    bool IsStalled() const override;

    void AddHigherLayeredPool(HigherLayeredPool* higher_pool) override;

    void RemoveHigherLayeredPool(HigherLayeredPool* higher_pool) override;

    // HigherLayeredPool implementation.
    bool CloseOneIdleConnection() override;

private:
    typedef ClientSocketPoolBase<SOCKSSocketParams> PoolBase;

    class SOCKSConnectJobFactory : public PoolBase::ConnectJobFactory {
    public:
        SOCKSConnectJobFactory(TransportClientSocketPool* transport_pool,
            HostResolver* host_resolver,
            NetLog* net_log)
            : transport_pool_(transport_pool)
            , host_resolver_(host_resolver)
            , net_log_(net_log)
        {
        }

        ~SOCKSConnectJobFactory() override { }

        // ClientSocketPoolBase::ConnectJobFactory methods.
        std::unique_ptr<ConnectJob> NewConnectJob(
            const std::string& group_name,
            const PoolBase::Request& request,
            ConnectJob::Delegate* delegate) const override;

        base::TimeDelta ConnectionTimeout() const override;

    private:
        TransportClientSocketPool* const transport_pool_;
        HostResolver* const host_resolver_;
        NetLog* net_log_;

        DISALLOW_COPY_AND_ASSIGN(SOCKSConnectJobFactory);
    };

    TransportClientSocketPool* const transport_pool_;
    PoolBase base_;

    DISALLOW_COPY_AND_ASSIGN(SOCKSClientSocketPool);
};

} // namespace net

#endif // NET_SOCKET_SOCKS_CLIENT_SOCKET_POOL_H_
